New details have emerged about the professor accused of Friday's shootings at the University of Alabama. NBC's Thanh Truong reports on Amy Bishop's past.

Crime and courts

This content comes from Closed Captioning that was broadcast along with this program.

>>for us tonight.

>>>we move to
huntsville
, alabama where the questions continue to pile up in a case of
amy
bishop,
university of alabama
professor accused of shooting six colleagues, killing three of them. she was arraigned today on murder charges, now some people are asking how she ever ended up on the faculty, given some of her trouble in her past. nbc's thanh truong reports from
huntsville
.

>>reporter: the
university of alabama
,
huntsville
is eerily quiet today, classes cancelled for the holiday are cancelled all week. flags fly half staff and flowers have been left in memory of last week's shooting. last week, gunfire broke the campus calm at the shelbey center where
amy
bishop suddenly opened fire, killing three of her colleagues and wounding three others. the 44-year-old was hoping for a tenured position but had been denied.

>>granting of tenure is a long and involved process, because as you know, the decision involves whether a professor will be effectively granted a position for the rest of their time at the university.

>>reporter: as the investigation into the killings deepen, police have discovered this is not dr. bishop's first encounter with deadly violence. that was 24 years ago, far from here, in her hometown of braintree, massachusetts and it involved her
younger brother
. 18-year-old seth bishop was killed after police say his older sister,
amy
shot him inside their home.

>>she shot her brother in the chest, fled the home, prior to fleeing the home, she fired one more round from the shotgun.

>>reporter: at the time it was ruled an accidental shooting, but questions are now surfacing. then in
1993
, as a doctoral student, she was questioned after a package containing two
pipe bombs
was delivered to the home of her professor, the device never detonated and authorities cleared bishop and her husband of any wrongdoing. tonight
amy
bishop, neurobiologist, mother of four is in jail awaiting a court appearance. and the campus community is preparing for a
memorial service
scheduled for week's end. thanh truong nbc news,
huntsville
, alabama.